The four colored buttons seen above are a product made by Learning Resources. They flash and make noise when pressed and are meant for quiz-show style games in the classroom. The problem is that they don’t use a central controller, so it’s up to the person running the game to judge who rang in first. [Kenny] fixed that issue by building his own controller which is housed in that black project box.
He went with an Arduino Uno board. It fits in the project box and has no problem monitoring all of the buttons and triggering their sound and lights when necessary. There are two telephone jacks (RJ11 connectors) on either side of the controller. He also cracked open each button, cutting some traces on the PCB in order to patch the signals into connectors he added to the housing.
The video after the break shows the system in action, In addition to illuminating the first button to ring in there are LEDs on the box that indicate who was 2nd, 3rd, and 4th in line.
If you don’t want to purchase buttons try making your own with some cheap plastic bowls.